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2.7.4 ASN oversight of reactor outages
Licensees need to periodically shut down their reactors
in order to renew the fuel, which becomes gradually
depleted during the operating cycle. At each outage,
one third or one quarter of the fuel is renewed.
These outages mean that it is possible to access parts of
the installation that would not normally be accessible
during operation. Outages are therefore an opportunity
to verify the condition of the NPP by running checks and
performing maintenance work, as well as to implement
the modifications scheduled for the NPP.
These refuelling outages can be of several types:
•
Simple Refuelling Outage (ASR) and Partial Inspection
(VP) outage: these outages last a few weeks and are
devoted to renewing part of the fuel and conducting
a programme of verification and maintenance that is
more extensive during a Partial Inspection (VP) than
during a Simple Refuelling Outage (ASR);
•
Ten-yearly Outage (VD): this outage entails a wide-
ranging verification and maintenance programme.
This type of outage, which lasts several months and
takes place every 10 years, is also an opportunity for
the licensee to carry out major operations such as a
complete inspection and hydrotest on the primary
system, a containment test or incorporation of design
changes decided as part of the periodic safety reviews.
These outages are scheduled and prepared for by the
licensee several months in advance. ASN checks the steps
taken by the licensee to guarantee safety and radiation
protection during the outage, and the safety of operation
during the coming cycle(s).
The checks carried out by ASN mainly concern the
following aspects:
•
during the outage preparation phase, the conformity
of the reactor outage programme with the applicable
baseline requirements. As necessary, ASN asks for
additions to this programme;
•
during the outage – through regular briefings and
inspections – the implementation of the programme
and the handling of any unforeseen circumstances;
•
at the end of outage, when the licensee presents its
reactor outage report, the condition of the reactor and
its readiness for restart. After this inspection, ASN
will either approve reactor restart or not;
•
after the reactor restarts, the results of all tests carried
out during the outage and during the restart phase.
All of these measures are provided for by ASN resolution
2014-DC-0444 of 15th July 2014 concerning pressurised
water reactor shutdowns and restarts.
2.8 Maintaining and continuously
improving nuclear safety
2.8.1 Management of subcontracted activities
The maintenance of French reactors is to a large extent
subcontracted by EDF to outside contractors, with the
total workforce representing about 20,000 employees.
EDF justifies the use of subcontracting by the need to
call on specific or rare expertise, the highly seasonal
nature of reactor outages and thus the need to absorb
workload peaks.
The nuclear licensee’s decision to resort to subcontracting
must not compromise the technical skills it must retain
in-house, in order to carry out its responsibility for
safety and be able to effectively monitor the quality
of the work performed by the subcontractors. Poorly
managed subcontracting is liable to lead to poor quality
of work and have a negative impact on the safety of the
facility and the radiation protection of those involved (the
subcontractors receive a large share of the dose linked
to the work done on all the reactors: see point 4.1.4).
These consequences can in particular result from the
use of insufficiently qualified personnel, insufficient
monitoring of the contractors by the licensee or degraded
working conditions.
Therefore, if the decision to outsource certain activities
is determined by EDF’s industrial policy strategy, the
conditions for the use of subcontracting must be such
that the licensee retains full responsibility for the safety
of its facilities at all times.
In addition, owing to the large number of nuclear reactors
operated by EDF, its outsourcing decisions have a direct
impact on the industrial fabric specialising in nuclear
supplies and maintenance.
A system of prior contractor qualification was put into
place by EDF. It is based on an assessment of the technical
know-how and the organisation of the subcontracting
companies. The principles are described in the “Progress
and sustainable development Charter” signedby EDF and
its main contractors. In 2013, the French nuclear sector
defined “social specifications” applicable to the provision
of services andwork performed in a nuclear facility. Since
July 2013, EDFhas transposed these social specifications
into its subcontracting contracts for reactors in operation.
Article 124 of Act 2015-992 of 17th August 2015,
concerning Energy Transition for Green Growth and
owing to the particular importance of certain activities
for protection of the interests mentioned in Article
L. 593-1 of the Environment Code, a decree of the
Conseil d’État
(Council of State) can regulate or limit
the use of service providers or subcontractors for the
execution of these activities. In addition, Article 124
states that the licensee must monitor activities important
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CHAPTER 12:
EDF NUCLEAR POWER PLANTS (NPPs)
ASN report on the state of nuclear safety and radiation protection in France in 2015